JPH02302019A - Solid electrolytic capacitor and its manufacture - Google Patents

Abstract

PURPOSE:To provide a capacitor having good characteristics and reliability and suitable for mass production by a method wherein a metal oxide layer is formed on the surface of an anodic formation film, a voltage is applied by using the metal oxide layer as an electrode and an electrolytic polymerization operation is executed. CONSTITUTION:For example, an aluminum foil is used as an anode body 11 composed of a valve metal; its surface is roughened electro-chemically; an anodic formation film is formed at a formation voltage of 35V; after that, it is cut off to be a shape having a plurality of protrusions 12. The anode body 11 composed of the valve metal and a comb-shaped electrode 14 are used; tips of the comb-shaped electrode 14 are brought into contact with parts to which a manganese dioxide layer 13 has been applied at the protrusions 12 of the anode body 11; this assembly is immersed in a polymerization liquid 15. The comb-shaped electrode 14 as a polymerization electrode is used as a positive pole; a constant voltage of 5V is applied for 20min between the comb-shaped electrode and a polymerization cathode 16. This polymerization operation is started from a contact part with the comb-shaped electrode 14 on the surface of the protrusions 12; a conductive high-polymer film is formed on the whole surface of the manganese dioxide layer 10 in 10 to 15min.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a solid electrolytic capacitor using a conductive polymer as a solid electrolyte and a method for manufacturing the same.

2. Description of the Related Art In recent years, as the power supply circuits of electronic devices have become increasingly high-frequency, electrolytic capacitors used therein are required to have excellent high-frequency characteristics. On the other hand, in order to achieve low impedance in a high frequency region, solid electrolytic capacitors have been proposed in which a highly conductive conductive polymer obtained by electrolytic polymerization is used as a solid electrolyte.

In solid electrolytic capacitors that use a conductive polymer as a solid electrolyte, a method of forming a conductive polymer layer on the anode chemical coating, which is an insulator, is to form a chemically oxidized conductive polymer film on the anode chemical coating. However, a method has been proposed in which electrolytic polymerization is carried out using this as an electrode. That is, (1) An anode chemical conversion film is formed on the surface of an anode foil such as a valve metal, and a chemically oxidized and polymerized conductive polymer film such as virol is formed on this anodic oxide film using an oxidizing agent. and a method in which a conductor is placed in contact with or within a distance of 1 mm from this chemically oxidized polymerized conductive polymer film, and electrolytically polymerized using the conductor as an anode (Japanese Unexamined Patent Publication No. Sho 64-32619).

(Takumi) A 1VAffi chemical conversion film is formed on the surface of an anode foil made of valve metal, and a chemically oxidized conductive polymer film such as pyrrole is formed using an oxidizing agent on this anode chemical film, and then There is a method (Japanese Unexamined Patent Publication No. 84-32620) in which the end portion of an anode foil made of metal is cut to expose the metal portion, and the exposed metal portion is subjected to electrolytic polymerization.

In the above examples, there is no particular mention of the case where electrolytically polymerized polymer films are to be formed on multiple devices at the same time, but in method (1), as shown in FIG. Then, a power supply electrode (hereinafter referred to as a polymerization electric kettle) 3 is brought into contact with each of the four anode bodies 2 made of valve metal, and this polymerization electrode 3 is used as a positive electrode, and an electric current is connected between it and the polymerization anode 4. In method (2), a configuration in which electrolytic polymerization is performed by applying FE, as shown in FIG. It is necessary to use the anodization 2 itself, which is υ, as a positive electrode and to apply a voltage to polymerize.

Problems to be Solved by the Invention However, in the conventional method (1) shown in FIG. 8, a polymerized electrode 3 is prepared for each capacitor element,
It requires a complicated process of bringing the valve metal into contact with each positive order body 2, which makes mass production difficult.

Although the conventional method shown in FIG. 9 has the advantage of being able to form an electrolytically polymerized polymer film on a plurality of elements with relative ease, Because the defective part (exposed metal part) and the conductive polymer layer that serves as the cathode come into contact, the product has disadvantages such as large leakage current and low withstand voltage, making it difficult to obtain a highly reliable solid electrolytic capacitor. .

Furthermore, in the above conventional methods (1) and (2), a halogen, a metal halide, or a protonic acid is used as an oxidizing agent in forming a chemically oxidized and polymerized conductive polymer film.

Since peroxide is used, there is great damage to the anodized chemical film, and as a result, it is difficult to obtain a solid electrolytic capacitor with low leakage current and high withstand voltage.

The present invention solves these problems, and aims to provide a solid electrolytic capacitor that has excellent characteristics and reliability and is suitable for mass production, and a method for manufacturing the same.

Means for Solving the Problems In order to solve the above problems, the present invention forms an anodic chemical conversion film on the surface of a comb-shaped anodization made of valve metal, and
! lIi! 1. A metal oxide is uniformly attached to the protrusions of the cylindrical body in the form of islands or layers, and a comb-shaped electrode is placed in contact with the metal oxide layer to reduce the protrusion properties of the anodized protrusions. A conductive film is formed by electrolytic polymerization, and then
The projections of the anode body are individually cut to form one capacitor element.

Effects According to the present invention as described above, a metal oxide layer is provided on the surface of the V4% chemical conversion coating, and the metal oxide layer is used as an electrode to conduct electric EE.
is applied to perform electrolytic polymerization, so there is no direct contact between the defective part of the anode foil and the conductive polymer layer that becomes the cathode.As a result, the solid electrolytic capacitor has excellent characteristics and reliability. can be obtained. In addition, by electrolytically polymerizing a conductive polymer film by contacting a comb-shaped electrode with a comb-shaped anode body made of 10,000 yen of valve metal, it is easy to electrolytically polymerize multiple capacitor elements at the same time, which facilitates mass production. is significantly improved.

EXAMPLE Hereinafter, an example of the present invention will be described based on the accompanying drawings of FIGS. 1 to 7.

FIG. 1('&) and FIG. 1(b) are a front view and a side view showing the construction of an electrolytic polymerization tank for producing the solid electrolytic capacitor of the present invention. FIG. 2 shows an example of the shape of a comb-shaped anode body made of valve metal. The anode body 11 made of valve metal is made of aluminum foil (thickness: 90 mm).
The surface thereof was electrochemically roughened using a 1000 μm), and an anodic chemical coating was formed at a chemical forming voltage of 35 V. Thereafter, the material was cut into a shape having a plurality of protrusions 12 as shown in FIG.

The dimensions of the protrusion 12 were 5 mm x IQ mm.

In order to form an anodic oxide film on the cut surface, a re-conversion anodic oxidation treatment was performed after punching. Although a rectangular example is shown as the shape of the comb-shaped anode body 11 made of valve metal, its shape and dimensions are not limited to this.

FIG. 3 shows a protrusion 1 of a comb-shaped anode body 11 made of valve metal.
2 shows a state in which a manganese dioxide layer 13 as a metal oxide is attached to No. 2. This manganese dioxide layer 13
is a protrusion 12 in a nitrate I-manganese aqueous solution with a specific gravity of 1.3.
It was formed by immersing it up to a predetermined portion and then thermally decomposing it at 205C for 6 minutes.

FIG. 4 shows details of the comb-shaped electrode 14. In this embodiment, a rectangular one is shown as an example of the comb-shaped electrode 14, but the shape is not limited to this. . Further, although stainless steel is used as the material for the comb-shaped electrode 14, it may be made of metal, or may be made of conductive gold/mold oxide or a conductive polymer. Similar results can be obtained by using a stainless steel surface coated with a virol polymer film.

Anode body 11 made of valve metal prepared as described above
As shown in FIG.
The tip of the comb-shaped electrode 14 is brought into contact with the part, and the polymerization liquid 16 (
Pyrrole Q, 9 mol/l/l, triinderovir naphthalene sulfonate 0.5 mol/l//IJ liter aqueous solution).

Electrolytic polymerization was carried out by applying a constant voltage of 6 V for 20 minutes between the polymerization negative layer 1e and the polymerization negative layer 1e using the comb-shaped electrode 14 as a polymerization electrode as a positive electrode. This polymerization started at the surface of the protrusion 12 where it came in contact with the comb-shaped electrode 14, and a conductive polymer film was formed on the entire surface of the manganese dioxide layer 13 in 10 to 16 minutes.

After forming this conductive polymer film, FIG. 6(a)
As shown in (b), a carbon paint layer 18 and a silver paint layer 19 are formed on predetermined portions of the conductive polymer film 1, and the protrusions 12 are individually cut at the cut points indicated by two-dot chain lines in the figure. It was cut into one capacitor element, and the cathode lead 2o was joined by soldering as shown in FIG. The anode lead 21 is welded to the part of the anode body 11 made of valve metal to which the manganese dioxide layer 13 and the conductive polymer film 17 are not attached.

FIG. 7 shows a perspective view of the appearance of a solid electrolytic capacitor according to an embodiment of the present invention.Epoxy resin was used as the exterior material 18, and the exterior was coated by powder coating.

Table 1 id Capacitance, tangent of loss angle, leakage current (1 ov applied,
This figure shows the initial characteristics of withstand voltage (product breakdown voltage when the voltage increases by 10 V/1 minute).For comparison, conventional example 1
Initial characteristics of a chemically oxidized conductive polymer film of virol formed on an anodic oxide film instead of the manganese dioxide layer 13 shown in this example, and the manganese dioxide layer 13 shown in this example as Conventional Example 2. Instead of the layer 130, a chemically oxidized conductive polymer film of virol is formed on the anodic oxide film, and the tip of the protruding part of the anode body made of metal is cut off to expose the metal part. The initial characteristics of the product obtained by electrolytic polymerization from the metal part are shown. In addition,
Ammonium persulfate was used as the oxidizing agent for chemical oxidative polymerization.

(Leaving space below) Table 1 As is clear from Table 1 above, the solid electrolytic capacitor according to the present invention has the features of low leakage current and high product withstand voltage, and is also more durable than valve metal. By the construction method using the comb-shaped anode body 11 and the comb-shaped electrode 14, it is easy to electrolytically polymerize a plurality of capacitor elements at the same time.

In the above embodiments, virol was used as the conductive polymer, but thiophene, furan, and their derivatives can be used in the same manner. Furthermore, although triinpropylnaphthalene sulfonate has been described as a supporting electrolyte, the present invention is not limited thereto.

Further, although an embodiment has been shown in which aluminum is used as the anode body 11 made of valve metal, tantalum, titanium, etc. may also be used.

Effects of the Invention As is clear from the description of the above embodiments, according to the present invention,
Because we use a method of electrolytically polymerizing a conductive polymer film by bringing a comb-shaped electric pupil into contact with a comb-shaped anode body such as a valve metal, it is possible to electrolytically polymerize multiple capacitor elements at the same time. As a result, mass productivity can be greatly improved.

In addition, a metal oxide layer is provided on the surface of the anode chemical conversion film, and electrolytic polymerization is performed by applying a voltage using this metal oxide layer as an electrode. The layers are no longer in contact, resulting in
A highly reliable capacitor with low leakage current and high withstand voltage can be obtained.

[Brief explanation of drawings]

FIG. 1 shows the configuration of an electrolytic polymerization tank for producing a solid electrolytic capacitor according to an embodiment of the present invention.
is a front view, ('b) is a side view, Fig. 2 is a front view showing the shape of a comb-shaped anode body made of valve metal, and Fig. 3 is a state in which a manganese dioxide layer is adhered on the comb-shaped anode body. A front view showing
Fig. 4 is a front view showing the shape of a comb-shaped electrode, and Fig. 5 is a diagram showing the same comb-shaped anode body with a conductive polymer film, a carbon paint layer, and a silver paint layer placed horizontally. ) is a longitudinal cross-sectional view, (
b) is a side sectional view, Fig. 6' is a vertical sectional view showing the lead pulled out from the individual capacitor element, Fig. 7 is an external perspective view of a solid electrolytic capacitor, and Figs. 8 and 9 are conventional electrolytic capacitors. FIG. 2 is a schematic diagram showing the configuration of a polymerization tank. 11... Comb-shaped anode body, 12... Protrusion, 13... Manganese dioxide, 14... Comb-shaped electrode, 16... Polymerization liquid, 16... polymerization reaction, 17... conductive polymer membrane, 18...
...Carbon paint, 19...Silver paint, 2o.
...Cathode lead, 21...Anode lead. Name of agent: Patent attorney Shigetaka Awano and 1 other person 1st floor
---NeS Yuki L7 and 1 Go 12-Protrusion f3-Man dioxide size t4-Sakasumi electric exposure I5-Polymerization solution tZ tZ tZ 13... Man dioxide you are fake Figure 3 Figure 4
-Guide! , pile height + gate Fig. 5 19-Collection 11 total layers (α) π ・-1 pole sort”
figure

Claims (4)

[Claims] (1) An anode chemical conversion film is formed on the surface of a comb-shaped anode body made of valve metal and has a plurality of protrusions, and a metal oxide is uniformly applied to the protrusions of the anode body in the form of islands or layers. A conductive polymer film is formed on the protrusion of the anode body by electrolytic polymerization using a comb-shaped electrode placed in contact with the metal oxide layer. A solid electrolytic capacitor characterized in that each capacitor is individually cut to form one capacitor element. (2) The solid electrolytic capacitor according to claim 1, wherein the metal oxide is a manganese oxide. (3) Forming an anode chemical coating on the surface of a comb-shaped anode body made of valve metal and having a plurality of protrusions, and uniformly applying metal oxide in the form of islands or layers on the protrusions of the anode body. and forming a conductive polymer film on the protrusion of the anode body by electrolytic polymerization using a comb-shaped electrode placed in contact with the metal oxide layer; A method for manufacturing a solid electrolytic capacitor, comprising the step of individually cutting the parts to form one capacitor element. (4) The comb-shaped electrode placed in contact with the metal oxide layer is made of a conductive metal, a metal oxide, a conductive polymer, or a composite thereof. A method for manufacturing a solid electrolytic capacitor according to claim 3.